Mountain papaya ( Vasconcellea pubescens A.DC.)
is described as trioecious in the centers of origin of
Ecuador, Colombia, and Peru. However, under cultivation
conditions in La Serena (30° S, 70° W), Chile, it is found
to be dioecious and monoecious. The objective was to
learn about the variations in floral expression of mountain
papaya. Flowers from monoecious and dioecious plants
were therefore identified and quantified during two
seasons. In vitro pollen germination ability was also
evaluated based on the factors of site, season, and plant sex.
Monoecious plant inflorescences are polygamous; female
and male flowers are observed, as well as bisexual flowers
that are usually deformed. This condition allows them to be
classified as an ambisexual plant. The existence of flowers
of different sexes appears to depend on the season; the
female dioecious plant is maintained as such, independently
of climatic conditions. Pollen from male flowers, from both
ambisexual and male plants, germinates 75% in summer,
while germination decreases to 56% in spring (P ≤ 0.05).
Flowering of female plants coincides with the permanent
occurrence of male flowers in ambisexual plants, which
ensures pollination without the need for male plants as
pollinators in orchards. Based on this information, some
management practices and possible lines of research about
this species are proposed.